#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <signal.h>
#include <unistd.h>
#include <stdlib.h>
#include <assert.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
/*
ssize_t send(int sockfd,const void *buf,size_t len,int flags);
send往sockfd写入数据，buf和len参数分别指定写缓冲区的位置和大小。send成功时返回
实际写入数据的长度，失败则返回－1并设置errno.
*/
int main(int argc,char*argv[])
{
    if(argc <=2)
    {
        printf("usage: %s ip_address port_number \n",
        basename(argv[0]));
        return 1;
    }

    const char* ip = argv[1];
    int port = atoi(argv[2]);

   

    /*创建一个IPv4 socket地址*/
    struct sockaddr_in server_address;
    bzero(&server_address,sizeof(server_address));
    server_address.sin_family = AF_INET;
    inet_pton(AF_INET,ip,&server_address.sin_addr);
    server_address.sin_port= htons(port);

    int sockfd = socket(PF_INET,SOCK_STREAM,0);
    assert(sockfd>=0);

    if(connect(sockfd,(struct sockaddr*)&server_address,sizeof(server_address)))
    {
        printf("connection failed\n");
    }
    else{
        const char * oob_data = "abcdefg";
        const char* normal_data  ="1234";
        //send(sockfd,normal_data,strlen(normal_data),0);
        send(sockfd,oob_data,strlen(oob_data),MSG_OOB);//发送紧急数据
        //send(sockfd,normal_data,strlen(normal_data),0);
    }
    close(sockfd);
    return 0;
}

